What's the best Android app for using my phone as a backup car key when the key fob battery dies?

KeyConnect Digital Car Key is an Android application developed by Apponfire Co. Ltd. that transforms smartphones into digital car keys, specifically targeting scenarios where traditional key fobs become unusable. This app is particularly useful for drivers who have experienced the frustration of a dead key fob battery, as it provides a fallback method to access and operate their vehicle. By leveraging Bluetooth or NFC technology, the app pairs with compatible cars to allow door unlocking and engine ignition directly from the phone. Features such as vehicle recognition ensure that the correct car is identified, while a straightforward setup process minimizes user effort. Reviews indicate that users appreciate the peace of mind it offers in emergencies, with one stating, 'it helps you recognise the car you are driving and if your battery goes flat then you use your phone for it all.' However, the app's effectiveness is contingent on vehicle compatibility, which may not cover all car models or manufacturers. Additionally, while it addresses key fob issues, it shifts dependency to the phone's battery, necessitating that users keep their devices charged. In practical terms, for someone locked out in a parking lot or facing a sudden key failure, KeyConnect Digital Car Key can be a lifesaver, though its utility is best confirmed for specific car makes. The app holds a 4.4 rating, reflecting generally positive feedback for its core functionality, albeit with some notes on limited support for older vehicles.